The following experiments are planned: (1) Certain physical, chemical, histochemical and ultrastructural characteristics of interceroids and ceroids formed in vivo in the crushed epididymal fat pad (CEFP)-model will be determined and compared in groups of rats fed a standard semi-synthetic diet containing high percentages of different types of natural fats. By this means it can be determined if varying the source of the pigments will produce predictable variations in the nature of the end product. (2) Interceroids will be produced in vitro for the purpose of testing out their absorbability when stomach-fed to rats. Disturbances in intestinal function (chiefly absorption) will be evaluated in these animals. It is hoped that this approach may lead to the development of one type of model resembling ceroid storage disease of children and possibly intestinal lypodytrophy (Whipple's Disease) in adults. (3) To evaluate in choline-deficient rats, the fibrogenic and possibly cirrhogenic potential of ceroids in the development of dietary cirrhosis. (4) To test the working hypothesis that ceroids and interceroids once formed may act as a nidus for the formation of more of the pigments. The CEFP-model will permit quantitative evaluation of this possibility.